1. Field of the Invention
The invention relates to a cylinder block of an internal combustion engine.
2. Description of Related Art
A passage through which oil or coolant flows is provided in a cylinder block of an internal combustion engine. This kind of passage is able to be formed by assembling a core in a mold and molding a cylinder block, and then removing the core from a sand removing hole provided in the cylinder block. Aside from this kind of method that uses a core, there is also a method of forming a passage inside a cylinder block using a cutting tool such as a drill, after molding the cylinder block.
When forming a passage in the cylinder block by these methods, the sand removing hole or the hole resulting from cutting ends up remaining in the surface of the cylinder block. Japanese Patent Application Publication No. 2011-158051 (JP 2011-158051 A) describes technology for closing off such a hole by press-fitting a sealing member into a press-fitting portion where the hole is open. As a result, oil or coolant that flows through the passage is able to be inhibited from leaking out.